Application of insulating material to electric cables



Oct. 28, 1947. MADDOCK 2,429,635

APPLICATION OF INSULATING MATERIAL T0 ELECTRIC CABLES Filed Dec. 15, 1944 INVENTOR Hum Tuunn Hapyoc.

AI'FORNE ratentea UCI. 0, IUI'I UNITED s'rarss PATENT" OFF-ICE APPLICATION OF INSULATING MATERIAL TO ELECTRIC CABLES Alan Julian Maddock, London, England, assignor to Standard Telephones and Cables Limited, London, England, a British company ApplicationDecember 15, 1944, Serial No. 568,376 In Great Britain December 24. 1943 her-coated tape it may be desirable to vulcanize the rubber during wrapping. In both these cases it is a question of applying heat to the tape during the wrapping process, and the present invention is concerned with the provision of a device or tool for effecting the simultaneous wrapping and heating.

The invention consists in such a tool comprising means for applying the tape to the cable and means for passing a high-frequency electric current through the tape at substantially the same time as the tape is being applied to the cable.

The description which follows relates to the accompanying drawings in which Figs. 1, 2 and 3 represent, in diagrammatic perspective, three embodiments of the invention.

In Fig. 1 is shown a cable having an inner metallic conductor W and an outer layer P of insulating material. Around this cable a tape T of insulating material is to be wound in acontlnuous P comprise thermoplastic material. The tool by which this simultaneous winding and heating is effected consists of a box B having a suitable handie H and having an extension arm on one side for carrying the spool or roll R of insulating tape.

The heating is effected by subjecting the tape, being a dielectric material, to a high-frequency electric current so that, as is well known, heating results from the high-frequency current passing through the dielectric. Accordingly a generator unit is housed within the box B, and one Of its output leads is taken directly to an electrode E, which forms the bottom of the box B and is shaped to the contour of the cable. The other lead L is taken from the box 13 to the inner conductor W of the cable.

In use the tape '1 from the roll R. is passed through a slot F in the curved electrode E on to the cable itself, so that as the tool is rotated by hand around the cable as shown by the arrow, the tape is unwound from the supply roll R and 8 Claims. (Cl. 57-6) ,2 wound onto the cable. frequency potential is applied across the tape and the insulation P on the cable between the outer electrode E and the inner conductor W. In this way the tape lying under the electrode E is heated, with consequent "welding to the cable insulation and to the adjacent layers oi' tape.

The progressive axial movement of the tool ensures that the tape is laid in helical form with any desired amount of overlap.

The element constituting the inner electrode of the high frequency system has been-shown as the innermost wire W; but obviously this is not necessarily so, and the choice will depend upon the structure of the cable being treated. For exam ple, as shown in Fig. 3, if there is a metallic braiding BR underneath the outermost layer of thermoplastic material, the lead L may be connected to this braiding instead of to the core. Again it may not be possible to obtain access to any me- In Fig. 2 the lead L of stout material is taken around in the circumferential direction to a counter-electrode C of any desired form. The electrode C is shown, for example, as comprising a wheel situated more or less diametrically opposite to the centre of the other electrode E.

What is claimed is:

1. A tool for winding tape onto a cable or the like comprising a high-frequency generator, a tape-spool carrier mounted on a. member adapted to engage the periphery of the cable under which member the tape from the Spool is fed onto the cable, an electrical connectlon'trom one output terminal or the generator to said member, and a lead from the other output terminal of the generator for making electrical connection to a metallic interior component of the cable.

2. A tool for winding tape onto a cable or the like comprising a high-frequency generator, a

tape-spool carrier mounted on one of a plurality of members adapted to engage the cable on substantially opposite sides and to press the tape frequency current and a, pair of electrodes for application of the high frequency current to the cable, and at least one or said electrodes being At the same time a high icausedzto move about the periphery of the cable 7 as-the tape is being wrapped therearound.

4.- .Atool for winding tape onto acable accordving-to'claim 3 wherein said one or said electrodes includes a portion shaped to conform-substanztially to the contour oi. the cable.

'5; A tool for winding tapeonto a cable accord- .fingzto claim 3 wherein said one of said electrodes includes a wheel adapted to contact the periphery of the cable.

6 6.- Atom for winding tape onto a cable accord- .=;-l ng to claim 3 wherein the other of saidelectrodes -includes means for connecting it to a conductor portion 01 said cable,

, .7. g A tool for-winding tape onto a cable accord- Qing to'claim 3 wherein the other of said electrodes ,.;lncll1des means for-locating it at a point circumferentially spaced around the cable from said one g, eleetrode.

8." Ajtool according-to claim 3 wherein said one 4 electrode includes a portion shaped to conform substantially-to the contour of the cable and the other oi said electrodes includeaa wheel adapted to contact the cable at a-point circumierentlally 5 spaced-about said cable from said one electrode.

ALANJULIANMADDOCK.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS 

